Although several new cases of largemouth bass virus (LMBV) were detected last fall, the majority of last year’s testing indicates that virus is on the decline in many lakes.

Samples were taken from 13 lakes in 2003 and sent to the U.S. Fish and Wildlife Service’s National Fish Health Center in Arizona. A total of 21 lakes have now tested positive for the virus, however only two documented fish kills have occurred in Oklahoma as a result of LMBV.

“We are pleased to see LMBV declining in lakes like Eufaula and Tenkiller and these results go along with our predictions that bass are developing natural immunity to the virus,” said Kim Erickson, fisheries chief for the Oklahoma Department of Wildlife Conservation. “However the virus remains at moderate levels in lakes like Hudson and Ft. Gibson. Fortunately we have not seen any documented fish kills in those lakes.”

The virus was first documented in the state at a LMBV fish kill in 2000 at Lake Tenkiller. As predicted, Tenkiller’s bass population is recovering and bass fishing appears to be returning to normal. The second was located at Wes Watkins Reservoir in central Oklahoma during the fall of 2003. The effects of this LMBV disease outbreak have yet to be determined.

“We will sample the lake again this spring to see if bass numbers and size structure have changed in order to get an idea of the impact,” Erickson said.

Not all bass that have the virus die from the disease. In fact, most bass that carry LMBV appear normal. In lakes where bass have developed the fatal disease, dying fish often swim near the surface and have trouble remaining upright. LMBV is not known to infect warm-blooded animals, including humans. Fish infected with the virus are safe to eat when properly cooked.

Since 2000, 26 lakes have been tested for LMBV. Lakes testing positive include Arbuckle, Eucha, Eufaula, Ft. Gibson, Grand, Hudson, Keystone, Konawa, Lawtonka, McGee Creek, Murray, Okemah, Oologah, Sardis, Skiatook, Sooner, Tenkiller, Texoma, Thunderbird, Webbers Falls and Wes Watkins. Lakes Arcadia, Bixhoma, Broken Bow, Crowder and Holdenville have so far tested negative for LMBV.

Biologists remain optimistic that Oklahoma waters seem to be following a similar pattern seen in other states where the virus runs it’s course and the big fish that are lost are replaced in the population by younger fish. Even in those lakes where the virus remains prevalent, biologists have not seen any major changes to the bass fishery.

“We will continue to monitor the status of LMBV and manage our bass populations across the state, and we will provide information to our anglers every chance we get,” Erickson said.

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